Weather by Month - Seattle
Temperature Comparison
The biggest temperature swing occurs between September and October, with a change of 6°C.
Jan
COLD
Feb
COOL
Mar
COOL
Apr
COOL
May
MILD
Jun
MILD
Jul
WARM
Aug
WARM
Sep
MILD
Oct
COOL
Nov
COOL
Dec
COLD
| Month | Low Temperature | High Temperature | Category |
|---|---|---|---|
| January | | | cold |
| February | | | cool |
| March | | | cool |
| April | | | cool |
| May | | | mild |
| June | | | mild |
| July | | | warm |
| August | | | warm |
| September | | | mild |
| October | | | cool |
| November | | | cool |
| December | | | cold |
Rain & Sunshine Patterns
Driest Months
#1 July
Best for: outdoor activities & sightseeing
#2 August
Best for: outdoor activities & sightseeing
#3 June
Best for: outdoor activities & sightseeing
Wettest Months
#1 November
Expect: possible showers, pack waterproofs
#2 December
Expect: possible showers, pack waterproofs
#3 January
Expect: possible showers, pack waterproofs
UV & Sun Protection Calendar
⚠️ High UV Alert: April, May, June, July, August require serious sun protection.
Jan
2
LOW-MOD
Feb
4
MODERATE
Mar
5
MODERATE
Apr
7
HIGH
May
7
HIGH
Jun
8
HIGH
Jul
8
HIGH
Aug
7
HIGH
Sep
6
MODERATE
Oct
4
MODERATE
Nov
3
LOW-MOD
Dec
2
LOW-MOD
Extreme (11+)
Avoid sun during midday, use SPF 50+
Very High (8-10)
Essential sun protection required
High (6-7)
Use SPF 30+, wear hat & sunglasses
Moderate (3-5)
Sun protection recommended
Low-Moderate (1-2)
Minimal protection needed
Low (0)
No protection required
Daylight Hours
Daylight varies from 8.5 hours in December (winter) to 15.9 hours in June (summer), which is a difference of 7.4 hours.
Shortest Days
December
8.5h
Average Sunrise:07:49
Average Sunset:16:19
Plan daytime activities for midday when light is best. Early sunsets mean evening plans should account for darkness.
Longest Days
June
15.9h
Average Sunrise:04:11
Average Sunset:20:07
Extended daylight perfect for evening activities and late dining. You can fit more sightseeing into each day.
Wind & Humidity Overview
Wind Conditions
Average wind speed
Windiest months:
November (11 km/h)
December (11 km/h)
January (11 km/h)
Packing tip: Conditions are generally calm, but a light layer is always handy.
Humidity Levels
Average humidity
78%
Most humid:
January (85%)
Least humid:
July (67%)
Packing tip: Choose breathable, natural fabrics like cotton or linen for comfort in humid conditions.
Seasonal Overview
Northern Hemisphere seasons shape the weather patterns throughout the year. Here's what to expect in each season:
Winter
January, February, December
Avg High 7°C
Avg Low 2°C
Avg Rain 160 mm
Cool weather; bring layers and a jacket
Spring
March, April, May
Avg High 14°C
Avg Low 5°C
Avg Rain 102 mm
Warming trend with frequent showers; pack waterproofs
Summer
June, July, August
Avg High 23°C
Avg Low 13°C
Avg Rain 37 mm
Comfortable temperatures; enjoy outdoor activities
Autumn
September, October, November
Avg High 15°C
Avg Low 8°C
Avg Rain 131 mm
Wet season begins; bring rain gear
Monthly Details
Click any month for detailed weather information and packing advice.
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View Best Time to VisitFrequently Asked Questions
When is Seattle warmest?
August is typically the warmest month in Seattle, with average high temperatures reaching around 24°C (75°F). This is peak summer weather, ideal for outdoor activities and sightseeing.
When is Seattle coldest?
February is usually the coldest month, with average low temperatures dropping to around 2°C (36°F). Pack warm layers if visiting during this time, especially for evening activities.
When does Seattle get the most rain?
November typically sees the most rainfall in Seattle, averaging around 196mm (7.7 inches). It's wise to pack waterproof layers and have some indoor backup plans if you're visiting during this month.
What is the driest month in Seattle?
July is typically the driest month, with average rainfall of just 22mm (0.9 inches). This makes it an excellent time for outdoor exploration and activities with minimal risk of rain disruption.
How much does the temperature vary in Seattle throughout the year?
Temperatures in Seattle range from average lows of 7°C (45°F) to highs of 15°C (58°F). This variation means you'll want to pack differently depending on when you visit—layers are key for adapting to the seasonal changes.
Do I need sun protection when visiting Seattle?
Yes, sun protection is important in Seattle. UV levels can reach 8 during peak months, which is considered high. Pack sunscreen (SPF 30+), sunglasses, and a hat, especially if you'll be outdoors for extended periods.